A major focus of companies today is the security and visibility of inventory throughout the supply chain. This is particularly important when management or processing of a high value asset is outsourced to another company. The use of Radio Frequency Identification (RFID) tags to facilitate item tacking is well known.
RFID tags are electronic devices that generally comprise a transponder and an integrated circuit programmed with unique identification information. In the context of a supply chain, RFID tags are located on items, and/or pallets of items, and may be used as a replacement for barcodes to identify items.
An RFID tag reader is used to read the unique data programmed on the RFID tag. An RFID tag reader is comprised of an antenna, transceiver, and a decoder, and can be configured either as a handheld unit, or as a fixed-mount device. The tag reader emits radio waves in ranges of anywhere from a few centimeters to about 40 meters, depending on its power output and the radio frequency used. When an RFID tag passes through the electromagnetic zone created by the tag reader, it detects the reader's activation signal. This electromagnetic zone energizes the RFID tag and enables the tag to transmit the data encoded on its integrated circuit. The reader decodes this data and the data is passed to a host computer for processing.
RFID tags are generally passive tags, as discussed above, in that they have no internal power source, and rely on an external source to provide power. In some instances, RFID tags may be active, in that they have an internal power source. Active RFID tags are more expensive and bulkier than passive RFID tags and, as such are generally not the preferred tracking device for item tracking.
Due to memory and processor limitations, the data stored on the RFID tag is generally little more than a unique identifier for the item. Hence, conventional systems offer little more than an electronic bar code that can be read from moderate distances.
A further disadvantage of conventional RFID tracking systems is the lack of synchronicity and integrity of the data across an entire supply chain. As different entities become involved in subsequent phases of the supply chain, the effective tracking of items from source to destination becomes complex and expensive. The integration of a company's backend systems with transport contractors and the like to enable auditing and tracking of the company's items throughout the supply chain is difficult and not scaleable.
For example, consider the situation where a transport contractor is used by a wide variety of companies to move freight. Each company has their own RFID system and the transport contractor has their own RFID system. While the transport company can read the data on the RFID tags for each company, the integration of the transport contractor's backend computer system with each company's is difficult and expensive and hence the companies have difficulty in accurately tracking their products throughout the supply chain.
Furthermore, RFID tags do not effectively solve the security requirements of governments and companies with high value assets. In order to meet these security requirements, and prevent theft and tampering using existing solutions it is required to install tag readers at every point between the manufacturer and consumer. This is clearly not a cost sensitive, scaleable or versatile solution to item tracking throughout the supply chain.
In another aspect of item tracking, it is desirable to communicate information from and/or to tracking devices associated with the items during their transit through the supply chain. Such tracking devices are typically disposed on the item, on the item packaging, or on a pallet upon which the items are disposed. Additionally, such items, and their associated tracking devices, may be collected into a storage area or container, and that storage area or container may provide one or more communication access portals through which inbound and outbound communication traffic must pass.
What is needed are methods and apparatus for allowing a plurality of low-power communication circuits having limited transmission range contained within the tracking devices to communicate through a communication access portal of a storage area or container.